Lubricating system for turbines and the like.



r O. D. H. BENTLEY.

LUBRICATING SYSTEM FOR TUBBINES AND THE LIKE.

APPLICATION FILED MAR. 27. 1917.

1 %9L3TQQ, Patented Jan. M, L919.

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mwmmmmwmmm OLIVER n. H. BENTLEY, 6F WEST ROXIBUIBIY, MASSACHUSETTEE, ILEESIGNOR- T 13. F.

STUJEtTlEVAllT CUMIPANY, 0F HYDE PARK. lltLhSSACl-IUSETTQ.

MASSACHUSETTS.

A CORPORPLHUN Uh LUBRICAIING SYSTEM FOR TUHBINJES All) THE llflffilllll.

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specification of Letters Patent.

Patented Jan, lid, rein.

Application filed March 27, 1917. Serial lilo. 157,5306.

12h all whom it may concern-x it known that l, OLIvnn l) H. BENTLEY, a citizen of the United States, residing at l l est lloirburyuin the coluity of Eilulfolk and State of lvlassachnsetts, have invented con tain new and useful Improvements in Lubricating Systems for Turbines and the like; and i: do hereby declare the following to be a full, clear, and exact description of the in vention, such as will enable others skilled in the art to which it appertains to make and use the same.

i i hcn. a steam turbine is in operation, there is always a diil'erence of pressure he tween the interior of the casing and. the atmosphere. ll here the turbine is used with out e condenser, the pressure within the casing is above atmosphere and the steam or vapor within the casing tends to flow along the bearing through which the turbine shaft emerges from thr using, thus displacing or mingling with the oil and interfering with the proper lubrication of the bearing.

Where a condenser is employed the pressure within the easing is below atmosphere and the tendency is for the outside air to work through the bearing into the casing with a similar interference with the lubrication. in orderto avoid this escape of steam from within the casing to the outer air, or the passage of air into the casingit has heretofore been found necessary to em 'iloy complex and bulky packingdevices and provide for diverting or collecting such or oil as hearing under the differences of pressure which erist at its opposite ends.

The object of the present invention is to produce a lubricating system, suitable for use with a stea1n-turbine or other machine in which a rotary shaft passes from a region of higher pressure to a region of lower pressure, in which the passage of fluid through the shaftbearing from the region of higher pressure is prevented or minimized, without the use of complex packing-devices or other bulky or expensive constructions.

To the foregoing end it is proposed, in accordance with the present'invention, to pi eat the passage of the fluid above referred to by balancing, against the pressure of such fluid, the pressure of the lubricating linidwith which the shaft-bearing is supplied, the two balanced pressures resulting ll ll may be carried through the in an equilibrium whereby movement or fluid in either direction is prevented or mininiizcd at the point of emergence of the shaft from the region of: higher pressure. In the preferred en'lbodimcnt of the invention the balance of pressures is maintained automatically, and the pressurc under which the lubricant is introduced. results in a constant flow of lubricant through the bearing, whereby constant and copious lubrication is in. snred.

Other objects of the invention, and the features of construction by which they are attained, will. be set forth in connection with the following description of the illustrated embodiment of the invention.

lfhe accou'ipanying drawing a diagramports the usual stationary elements of the v turbine. The rotor is mounted upon a shaft 3 by which the power is transmitted to the exterior of the casing. The exhaust steam is discharged first into the casing, and escapes thence through an exhaust opening 31 in the usual manner.

in. turbines of the illustrated type it has been common heretofore to provide packed joints at the points of emergence of the shaft from the casing, and to separate the bean ings, in which the shaft turns and, is supported, from these joints by a space sufficient to permit the escape of any steam or condensed mixture which escapes through the packing. 'By the use of the present in vention, however, the bulk and complication of such an arrangement is avoided, and the bearing-bushings 41, in which the sh aft turns, are mounted directly in sleeves 5 projecting integrally from the walls of the casing, so that the bearings are subject, at their inner ends, to whatever pressure may be within the casing. Where the turbine 'is not used with an exhaustcondenser there is a continu' ous pressure of the exhaust-steam within the casing, although this pressure varies, in any given installation, according to the volume and the temperature of the steam which is being used at the moment to drive the turbine.

The lubricating oil is contained in a reservoir 6 of suflicient capacity to provide for a long period of operation of the turbine, and the lubricant is drawn from the reservoir by a pump 7, through an outlet-pipe 8 which connects the intake of the pump with a point in the lower part of the reservoir. pump 7 may be a rotary ump or gear-pump of any ordinary or suitable form, and it is actuated b connection with the reduced end of the sha 3, as shown in the drawing.

The pump produces a constant flow of oil, which is discharged through pipes 9 and 10, and through the intermediate regulatingdevice which will be presently escrlbed, into annular channels 11 formed, respectively, near the inner ends of the bearingbushings 4. The oil so forced into these channels tends to flow in both directions between the adjacent surfaces of the shaft and each bearing-bushing, but the flow of the oil inwardly, or toward the casing, is prevented by the pressure of the steam or vapor within the turbine casing. Accordingly, the oil flows only outwardly through the bearings so as to lubricate them substantially from end to end with a constantly renewed supply of oil.

The automatic means for balancing, with approximate accuracy, the pressures, of the steam and the oil comprise a diaphragm casing. having lower and upper members and 13, respectively, secured together per1pherallv so as to form a chamber which is divided by a flexible diaphragm -14 clamped, at its edge, between the casing-members. The pipes 9 and 10 communicate with the space-beneath the diaphragm, while thespace above the diaphragm is connected, by a pipe 15, with the turbine-casing. The diaphragm-casing is also connected, at. its lower part, with the oil-reservoir 6 by a passage 16, and the entrance to this passage is controlled by an escape-valve l? which is attached to the diaphragm 14.

The punlp 7 is made of such capacity that it produces, at all times, a flow of oil in excess of that which ill pass through the shaft-bearings. The surplus oil is discharged through the passage 16, and thus returned to the reservoir. The flow through this passage is controlled by the valve 17, in accordance with the relative degrees of pressure above and below the diaphragm. Assuming that the normal position of the diaphragm and the valve issuch that the latter is somewhat raised from its seat, as shown in the drawings,- whenever the pressure of the oil beneath the diaphragm tends to exceed the steam pressure, communicated through the pipe 15, the diaphragm bulges upwardly, thus moving the escape-valve to The .a more widely open position and relieving the excessive oil-pressure by diminishing the resistance to the escape of the surplus oil. On the other hand. if the rises or the efliciency of the. oil pump is, through any cause. diminished so that the oil-pressure beneath the diaphragm tends to fall below the steam-pressure. the opposite effect results and the escape-valve is moved to a more nearly closed position, thus building up the oil-pressure so as to cause it to equal the. steam-pressure.

Since it is not practically possible to so construct the diaphragm and the escapevalve that they will secure exactly the desired result, means are preferably pro vided for adjusting the action oi these parts. To this end a leaf-spring is may be fixed, at one end. in the diaphragm-casing and connected at the other end. with the middle of the diaphragm. An adjusting- Screw '19 bears against the upper surface of the spring 18, and by manipulation of this screw the effect of the spring upon the diaphragm may be adjusted to secure any desired conditions of balance.

The ideal operation of the apparatus is one in which there is an exact balance between the stcam-pressnre and the oil-pressure. Since it is not practically possible to secure this absolute balance under varying conditions of operation, it is preferable to so adjust the parts that whatever slight difference may occur in the two pressures will be in favor of the steam pressure, so that whatever leakage occurs will be leakageof steam or water outwardly, rather than an inward leakage of oil. Such leakage, occurring under a very slight difference of pressures within and without the casing. may be rendered practically negligible by the use of a simple form of packing around the shaft at the inner end of each bearingbushing. In the drawing packing-rings 2+ are shown as seated in the inner portions of the sleeves 5, and the bushings 4 are arranged to be used as glands to compress these packing-rings, the bushings being movable endwise in the sleeves. and being adjustablv secured in .place by screws 25 passing. through flanges at the outer ends of the bushings. Endwise movement or thrust in the turbine-shaft is sustained by thrustcollars 26, screwed on the ends of the shaft andbearing against the outer ends of the bearing-bushings.

To assist in adjusting the lubricating-apparatus to secure the desired balance or slight difference of pressures, pressure-indicating means may be employed to indicate the relative degrees of pressure in the turlune-casing and in the lubricating system. For this purpose the drawing shows a device in the nature of a U-t-nbe. One limb 20 of this tube is made of glass, while the other steam-pressure naansra and shorter limb is formed by a pipe 21 which communicates with the interior of the turbine-easing. The upper end of the glass tube 20 is connected, by a riser-pipe 22, with one of the oil-channels 11. The pipe 22 and the upper part of the glass tube are normally filled with air, which is compressed, through the pipe 22, by the oil. The lower parts of the glass tube and the pipe 21 are filled with water of condensation from the turbine-casing. hen the steam-pressure and the water-pressure are equal the surface of the water in the tube 20 will be on a level with the horizontal part of the pipe 21, and any difi'crence in the pressures in question will be indicated by the water-level rising above or falling belo this median point. A scale 23 may be tired adjacent the glass tube to indicate the degree of difierence in pressures.

Since the oil in the passages, 11 is maintained at a substantialpressure above that of atmosphere, there is a constant outward flow of oil to the bearings, this oil escaping at the outer ends of the bearings. In order that the oil may not be lost, but may be contiuuall y collected and returned to the bearings, an oil-tight cap 27 is fixed at the outer end of each sleeve-bearing 5, and the oil which escapes from the bearings is whirled from the thrust-collars '26 against the .walls ot the caps, and is then drained from the bottoms of the caps through return pipes 28, which conduct it back into the reservoir 6. The reservoir is replenished, when necessary, by introducing oil through a filleropening 29, which is closed by a suitable plug and is formed, for convenience, in one of the bearing-caps 27.

Since what little leakage may occur through the passage 24: is leakage of water outwardly from the turbine-casing, this water will mingle with the oil passing through the bearings and will finally be conducted to the reservoir 6 with the returning oil. The outlet-pipe 8 communicates with the reservoir at a point somewhat above the bottom of the latter, so that aspace is at forded in which such water may collect and be separated from the oil, and at suitable intervals the water together with any sediment or spent oil, may be drawn ofl' from the reservoir through a tap 30.

The pressure of the exhaust-steam within the turbine-casing tends to rise and fall according to the volume and temperature of the steam by which the turbine is actuated, and under most conditions of operation the speed of thc'turbine varies in accordance with the same factors, the speed and the exhaust-pressure thus rising and falling together. Since the pump 7 is driven by the turbine-shaft, its speed of operation rises and falls with that of the turbine, and hence the volume of oil which is pumped rises and falls coincidently. It W111 be apparent,

- fixed size, necessarily results in an increased oil-pressure. Such an. arrangement is, ac-

cordingly, within the purview of the present invention, but it is preferable to employ a more sensitive and accurate device for regi i v a ulatmg the oil-pressure, and tor this purpose is preferable to employ, as shown in the draw1ng, a device such as the diaphragm 14, f, hich controls the escape-opening in accordancewith the two pressures to which it is subjected in opposite directions.

,The invention is not limited to the embodimentthereof herein described and illustrated in the accompanying drawings, but it may be embodied in various other forms within the nature of the invention as it is defined in the following claims.

The invention claimed is:

1. In combination with the casing and the shaft of a. stea1n-turbine or the like, and a shaft-bearing subject, at one end, to the pressure in the casing; means for forcing lubricant continuously into the bearing adjacent said end thereof; and means for automati- 100 cally maintaining the pressure of the lubricant at an approximately constant slight difference from the pressure in the casing.

, 2. In combination with the casing and the shaft of a steam-turbine, or the like, and a 106 shaft-bearing subject, at one end, to the pres sure in the casing; a conduit for introducing lubricant into said bearing; means for forcing constantly, into said conduit, a surplus of lubricant under pressure; a waste- 110 valve through which excess lubricant escapes a member connected with and controlling said valve, said member being subjected, in opposite directions, to the pressure of the lubricant in the conduit and pressure of the 11d fluid in the casing; and'means for subjecting said member to an adjustable constant force in aid of one of said pressures.

8. In combination with the casing and shaft of a steam-turbine or the like, and ai -20 shaft-bearing subject, at its ends, to diderent pressures and'at one end to the pressure in the casing; a conduit for introducing lubricant into said bearing; means for forcing constantly, intosaid conduit, a surplus of 1% lubricant under pressure; a waste-valve through which the excess lubricant escapes actuated by the difi'erence between the higher pressure to which the end of the bearing is subjected and the pressure in the conduit; 13W

and means for adjusting the waste-valve to vary the pressure difference required to actuate the same.

4. In combination with shaft of a steam-turbine or the like, and a shaftbearing subject, at one end, to the pressure in the casing; a conduit for introducing lubricant into said bearing; means for forcing constantly, into said conduit, a surplus of ubricant under pressure; a wastevalve through Which the excess lubricant escapes; a member connected with and controlling said valve, said member being subjected, in opposite irections, to the pressure of the lubricant in the conduit-and the pressure of the fluid in the casing, so as to maintain automatically a predetermined relation between said pressures; and means adjustable by the operator for supplementing the pressure upon the member in one direction.

5. In combination with the casing and the shaft of a steam-turbine or the like, and a shaft-bearing subject, at one end, to the pressure in the casing; means for forcing lubrithe casing and the cant continuously into the bearing adjacent said end thereof; adjustable means for automatically maintaining a predetermined relation between the pressure of the lubricant and the pressure in the casing; and devices for indicating said pressure relation.

6. In combination with the easinq and the shaft of a steam-turbine, or the lilie, and a. shaft-bearing subject, at one end, to the pressure'in the casing; a conduit for introducing lubricant into said bearing; a. reservoir; a pump for drawing a surplus of lubricant from the reservoir and introducinp it under pressure to the conduit; an escape valve for returning the excess lubricant from the conduit to the reservoir; a diaphragm controlling the escape valve and subject on one side to the pressure of the lubricant in the conduit and on the other side to the pressure in the casing: and an adjustable spring for supplementing the pressure on one side of the diaphragm.

OLIVER D. H. BENTLEY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Weuhmmon, 3. 0." 

